Very simply, if you don't have some kind of exit strategy, there's potentially unlimited loss/drawdown on any trade, or (if you're using some kind of grid) set of trades. If you're willing to live with that, fine; it's a personal decision. But I would say two things: (1) allowing the potential for large drawdown on one particular trade is effectively concentrating extensive risk on a single outcome, making correct forecasting even more imperative; and (2) never underestimate the truth in Keynes' words "the market can remain irrational longer than any trader can remain solvent".

Using lower leverage will allow you to survive longer, but it reduces both risk and return in like proportion, slowing rate of recovery from drawdown. If you then increase leverage in an attempt to accelerate this recovery, then you risk increasing further loss, also. I don't know of a way to "manage out of losing positions" without also increasing risk in some way. MM in itself can never provide an edge.

Having the courage to stomach drawdown does not, in itself, guarantee success.

Floating losses suddenly become very real when your account eventually hits a margin call. I know that from personal experience. Survival through risk management must always be a trader's uppermost priority. Ignore it at your peril.